The former presidential candidate, Mitt Romney, has urged his party to listen to prominent figures from Democratic-leaning and swing states such as Chris Christie, the New Jersey governor who is distrusted by many conservatives in the US.

In his first public speech since his defeat at the hands of Barack Obama in November, Romney said the Republican party should "learn from my mistakes" in order to win future elections.

Speaking to the Conservative Political Action Conference (CPAC) outside Washington DC, Romney thanked activists who had supported him. But he also made a point of urging the party to listen to the experiences of Christie and other governors from "blue and purple states" – an indication that he believes the GOP cannot win elections if it is perceived as being too rightwing.

Organisers of CPAC, the biggest annual gathering conservatives in the US, notably did not invite Christie to speak at this year's conference. Christie is blamed in some quarters for the Republicans' defeat in the presidential election, after he praised the performance of Obama in the aftermath of Hurricane Sandy.

At the conference, Romney emerged to the sound of Kid Rock's Born Free – his campaign anthem – and had to wait a full minute before the standing ovation died down. "You have touched my heart again," the former Massachusetts governor said as he beckoned the crowd to fall silent.

Reflecting on the 2012 campaign, Romney said he had "left the race disappointed that we didn't win". He urged the party to learn lessons from the campaign: "It is up to us to make sure that we learn from my mistakes, and from our mistakes, so that we can win the victories those people and this nation depend upon.

"As someone who just lost the last election, I'm probably not the best person to chart the course for the next election. That said, I do have advice. Perhaps because I am a former governor, I would urge you to learn the lessons that come from some of our greatest success stories: the 30 Republican governors."

Speaking in the Potomac ballroom at the Gaylord convention center outside Washington, Romney insisted that "we need the ideas and leadership of each of these governors". He said: "We particularly need to hear from the governors of the blue and purple states, like Bob McDonnell, Scott Walker, John Kasich, Susanna Martinez, Chris Christie, and Brian Sandoval, because their states are among those we must win to take the Senate and the White House."

Romney also used his speech to underline the need for the US to protect its position as a superpower, and to criticise China – a common theme of his campaign.

"It is no secret that the last century was an American century. And it is no secret that over the span of the 21st century, America's pre-eminent position is far from guaranteed," he said.

"The consequence if America were to be surpassed would be devastating. Why? Because among the primary rivals for world leadership – China, Russia, and the jihadists – not one believes in the freedoms we take for granted. Freedom depends on American leadership."

Romney praised his former running mate Paul Ryan, who spoke at CPAC on Friday morning and who is seen as one of the favourites for the Republican nomination in 2016.

"We can also learn from the examples of principle, passion and leadership that we have seen during these last several weeks from fellow conservatives here in Washington. I may be a little biased, but I applaud the clear and convincing voice of my friend, Paul Ryan," he said.

Romney spoke after Rick Santorum, his one-time competitor for the nomination, had given an emotional address at CPAC, a day after the death of his nephew. Santorum delivered a cerebral defence of social conservatism and warned the GOP against abandoning his principles. He criticised "those in the movement who want to abandon our moral underpinnings to win" and asked: "What does it profit a movement to gain the country but lose its own soul?"